To ensure unrestricted data transmission in plug connectors for Ethernet applications, such connectors must meet certain requirements, for example in terms of near end crosstalk (NEXT), far end crosstalk (FEXT), return loss, loss, which are also specified, for example, in DIN-EN 50173. Design parameters for the optimization of the high-frequency performance (HF performance) of differential data pairs include, for example, the dielectric constant of the insulating material used, the geometric distance of the pairs from each other, or the thickness of the wires or contacts. In a module or device made up of individual components, a certain HF performance is determined by the individual performance of each component.
In telecommunication and/or office application technologies, it is common practice to use modular plug connections, such as the RJ-45 connector, in which the contacts to be connected to mating contacts are in a parallel or in-line arrangement. In these fields, it is common in the art that an element, such as a printed circuit board, which connects the individual components, is provided with inductive and/or capacitive coupling features to compensate for the previously negative performance, so that the module meets requirements such as Cat5 (in accordance with DIN EN 50173).
There is ample prior patent or patent application documents in the field of telecommunication and/or office application technologies, including, for example, EP 1 063 734, EP 1 096 620, EP 1 170 834, EP 1 414 115, U.S. Pat. No. 5,310,363, U.S. Pat. No. 5,326,284, U.S. Pat. No. 5,997,358, U.S. Pat. No. 6,099,357, U.S. Pat. No. 6,319,069, U.S. Pat. No. 6,402,560, U.S. Pat. No. 6,840,779, US 2004/0147165, US 2005/0277339, US 2006/0160428, WO 01/80376, WO 02/17442, WO 2005/081369, WO 2005/117200, WO 2006/017332, WO 2006/062794 and WO 2006/068974.
Thus, the application and technology of structured cabling of office buildings are introduced and developed to a point where now new standardization efforts are being undertaken to transfer the achievements from the office world to the industrial environment. However, unlike the tree and star topologies commonly used in the office and telecommunications world, line and ring topologies are preferable in an industrial environment. Moreover, in addition to voice and conventional data transmission, open- and closed-loop process control systems are required to function reliably under all operating conditions, which, in addition to increased environmental requirements in various industrial fields, also increases the reliability requirements.
As a consequence, the different requirements of the telecommunication and/or office application technologies on the one hand, and the industrial environment on the other hand, inevitably lead to different plug connection variants, and the design approaches developed for modular plugs used in the telecommunication and/or office application technologies are not easily applicable to industrial plug connectors.
In the field of industrial plug connectors, two tendencies have emerged. First of all, commercially available RJ45 connectors, such as are known from the field of office communication, are prepared by external packaging for use in an industrial environment. In particular, different housing variants for rough environmental conditions are available, into which RJ45 connector inserts for 100, 250 or 600 MHz may be inserted, providing a shielded or unshielded configuration. The housing variants differ in shape (round or rectangular connector housing), locking devices (screw-type locks, bayonet locks, latching levers, push-pull locks), and specific properties, and are often not plug-compatible.
Secondly, connectors which are widely used in the industrial environment, such as the M12 round plug connector, which has been introduced at the field bus level in many applications for rough environmental conditions, are modified in terms of their inner structure in such a way that they can meet the data transmission requirements. In the field of M12 connectors, there are now available Cat5-compliant 4-pole plug connectors, both as patch cables and in a version that can be assembled in the field.
When the signal multiplexing technology is used to achieve higher transmission rates, more data pairs, at least 4 data pairs, are needed which, so far, are commercially available only as preassembled, Cat5-compliant M12 patch cables in an 8-pole version.
Document WO 01/86760 A1 describes an electrical plug connector in the form of a T-coupler, in which plug contacts and screw-on modules are connected to a printed circuit board by solder contacts.
Document WO 02/0717442 describes a communication connector with inductive compensation, in which are provided a printed circuit board having wire trace layers and inter-digitated capacitance.
Document DE 102 55 190 A1 describes a round plug connector unit for free assembly and connection of flexible cables.